Battery temperature sensors are a feature found on the charging systems of modern vehicles. With the continuously advancing electrical systems found on newer vehicles, batteries are becoming an increasingly important component to modern cars.

As its name suggests, battery temperature sensors detect the temperature of the battery so that the charging system voltage can be increased or decreased according to the vehicle’s needs. When the battery temperature is low, the system voltage is set high and will automatically decrease as the temperature increases. For this reason, when the battery temperature sensor fails, it can cause problems not only for the battery, but the entire electrical system as well. When the battery temperature sensor fails, the vehicle will usually produce a few symptoms that can notify the driver that a problem has occurred and should be serviced.

1. Engine surging

A symptom commonly associated with a failing battery temperature sensor is an engine that surges during operation. The battery temperature sensor helps the system continuously adjust the system voltage, and if it fails, this process may be disturbed. An incorrect or inconsistent signal from the battery temperature sensor may cause the system voltage to fluctuate, which will cause the engine to surge.

2. Low battery voltage

Another symptom of a bad or failing temperature sensor is low battery voltage. If the battery temperature sensor has any issue that causes it to send an incorrect signal to the computer, it can interfere with proper charging and cause low voltage. A battery with low voltage may not be able to properly start a vehicle, and may also cause other problems for the vehicle’s electrical system.

3. Illuminated Battery Light

If the battery temperature sensor fails, it can also cause the Battery Light to become illuminated. If the system is affected in any way that causes the battery to not be charged, and it is picked up by the computer, it will illuminate the Battery Light. The Battery Light may also be illuminated if the sensor detects that it is too hot, to alert the driver to shut off the vehicle before damage occurs to the battery.

While they are not a feature found on all vehicles, battery temperature sensors are becoming more common as the electrical systems of newer vehicles continue to advance, and these sensors can play an important role in a vehicle’s charging system. For this reason, if you suspect that your battery temperature sensor may be having an issue, have the vehicle diagnosed by a professional technician, such as one from YourMechanic. They will be able to determine if the car needs a battery temperature sensor replacement, or if any other repairs are needed to have your symptoms solved.

This article originally appeared on as Symptoms of a Bad or Failing Battery Temperature Sensor and was authored by Ed Ruelas.

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